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Transition Metal‐free C−H Sulfonylation and Pyrazole Annulation Cascade for the Synthesis of 4‐Sulfonyl Pyrazoles
Author(s) -
Tian Lihong,
Wan JiePing,
Sheng Shouri
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.202000244
Subject(s) - pyrazole , sulfonyl , annulation , chemistry , catalysis , reagent , combinatorial chemistry , transition metal , organic chemistry , alkyl
A practical protocol for the synthesis of 4‐sulfonyl pyrazoles via the reactions of readily available N,N ‐dimethyl enaminones and sulfonyl hydrazines has been developed via the catalysis of molecular iodine in the presence of TBHP and NaHCO 3 at room temperature. The pyrazole products have been constructed via the tandem C(sp 2 )−H sulfonylation and a pyrazole annulation without employing any transition metal catalyst or reagent, thus providing a practical new method for the synthesis of the novel pyrazoles bearing a sulfonyl side chain in the heterocycle.